BP1 is a member of homeobox genes, which are a family of regulatory genes encoding transcription factors that are vital for all aspects of growth and differentiation. The deregulated expression of homeobox genes has been described in many solid tumors and derivative cell lines. Among these, HOX, HSIX1 and PAX have been shown to promote cellular transformation in breast cancer. Recent studies demonstrate that homeobox genes impinge on the cell cycle, indicating that deregulation of cell cycle control might be a common mechanism by which aberrant homeobox gone expression contributes to carcinogenesis. This application will focus on the role of deregulated BP1 expression in cell cycle control in breast carcinogenesis. The oncogenic potential of BP1 will be established using clonogenicity and anchorage-independent growth studies by overexpressing BP1 in normal or Iow-BP1 expressing mammary cell lines. The downstream BP1 targets will be discovered using a microarray approach. Furthermore, the potential regulatory pathway of BP1 during cell cycle progression will be elucidated. These studies would potentially establish BP1 as a biomarker in breast cancer diagnosis and treatment.